package com.ny.zmb.openapi.ysutil.utils;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.io.IOException;
import java.security.SecureRandom;


/**
 * @类名称：JDES
 * @类描述：DES加密工具类。支持对文件的加密
 */
public class DESUtils {

	private final static String ENCODE_GBK = "GBK";
	private final static String ENCODE_UTF8 = "UTF-8";
	private final static String DES = "DES";

	/**
	 * Description 根据键值进行加密
	 *
	 * @param data
	 * @param key 加密键byte数组
	 * @throws Exception
	 */
	public static String encrypt(String data, String key) throws Exception {
		byte[] bt = encrypt(data.getBytes(ENCODE_GBK), key.getBytes(ENCODE_GBK));
		String strs = Base64Utils.encode(bt);
		return strs;
	}

	/**
	 * Description 根据键值进行解密
	 *
	 * @param data
	 * @param key 加密键byte数组
	 * @return
	 * @throws IOException
	 * @throws Exception
	 */
	public static String decrypt(String data, String key) throws Exception {
		if (data == null)
			return null;
		byte[] buf = Base64Utils.decode(data);
		byte[] bt = decrypt(buf, key.getBytes(ENCODE_GBK));
		return new String(bt, ENCODE_GBK);
	}
	
	/**
	 * Description 根据键值进行加密
	 *
	 * @param data
	 * @param key 加密键byte数组
	 * @throws Exception
	 */
	public static String encryptByUTF(String data, String key) throws Exception {
		byte[] bt = encrypt(data.getBytes(ENCODE_UTF8), key.getBytes(ENCODE_UTF8));
		String strs = Base64Utils.encode(bt);
		return strs;
	}

	/**
	 * Description 根据键值进行解密
	 *
	 * @param data
	 * @param key 加密键byte数组
	 * @return
	 * @throws IOException
	 * @throws Exception
	 */
	public static String decryptByUTF(String data, String key) throws Exception {
		if (data == null)
			return null;
		byte[] buf = Base64Utils.decode(data);
		byte[] bt = decrypt(buf, key.getBytes(ENCODE_UTF8));
		return new String(bt, ENCODE_UTF8);
	}

	/**
	 * Description 根据键值进行加密
	 *
	 * @param data
	 * @param key 加密键byte数组
	 * @return
	 * @throws Exception
	 */
	private static byte[] encrypt(byte[] data, byte[] key) throws Exception {
		// 生成一个可信任的随机数源
		SecureRandom sr = new SecureRandom();

		// 从原始密钥数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);

		// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey securekey = keyFactory.generateSecret(dks);

		// Cipher对象实际完成加密操作
		Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

		// 用密钥初始化Cipher对象
		cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);

		return cipher.doFinal(data);
	}

	/**
	 * Description 根据键值进行解密
	 *
	 * @param data
	 * @param key 加密键byte数组
	 * @return
	 * @throws Exception
	 */
	private static byte[] decrypt(byte[] data, byte[] key) throws Exception {
		// 生成一个可信任的随机数源
		SecureRandom sr = new SecureRandom();

		// 从原始密钥数据创建DESKeySpec对象
		DESKeySpec dks = new DESKeySpec(key);

		// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
		SecretKey securekey = keyFactory.generateSecret(dks);

		// Cipher对象实际完成解密操作
		Cipher cipher = Cipher.getInstance(DES);

		// 用密钥初始化Cipher对象
		cipher.init(Cipher.DECRYPT_MODE, securekey, sr);

		return cipher.doFinal(data);
	}
}
